Re: CPU <> Memory chip communication interface

Aug 05, 2005 15 Replies

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That's pretty fundamental. The classic example is to compare electricity to water.

Voltage is like water pressure - current is like water flow. With no pressure no water flows. The larger the pipe ( less resistance to flow ) the more water flows. In a similar way, the less electrical resistance, the more Amps flow in a circuit for a given voltage.

Reduce the pressure ( Volts ) and the flow ( current ) will reduce likewise.

You sound interested in electronics. An admirable interest.

Why not do what I did when young and simply do some self-study ? Books can be good you know ! Maybe today's way of living tends to overlook this obvious source of excellent info ?

Now - please stop trolling here.

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Graham

Nice introduction to signals across a wire.



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I never understood the difference between voltage and ampere... to bad this page doesn't discuss how ampere is related to voltage. (voltageampere very confusing )



One thing I do understand now. The higher the voltage the higher the one ;) (or maybe is ampere at work here as well ? )



Another surprising things is ;) +voltage is zero and -voltage is one. I would have done it the other way around... 1 is closer to positive so



+voltage is 1 and -voltage is closer to zero so -voltage is 0.

Bye, Skybuck.


Yeah ! No surprise sunshine ! Why not simply do some self-study ? It worked for me.

Graham

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That would be exceptional and irrelevant to any sensible understanding.

I'm getting bored of your trolling now.....

Graham

Here is another nice advanced introduction to signals over wires or other mediums:

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It also mentions modulation. So maybe the ReadBit/WriteBit functions should communicate with another little communication chip on the cpu itself. So that the cpu itself can simply communicatie with this little communication chip in a very simple way. The communication chip can then communicate with the main memory chip which might also have such a communication chip ;)

Lol sounds a lot like athlon's x2 design... a cpu chip with another chip inside it...

I have no idea what a north bridge and south bridge chip is... but could this be the same design ? :):):)

Bye, Skybuck.

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this

;)

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this

to water.

pressure no water

flows. In a similar

given voltage.

Does this mean a pipe diameter (of a certain material) always allows a certain maximum voltage ?

So if the source of the voltage becomes to high the pipe blows ? :)

Probably yes, ok that's easy.

Now what about two different pipes:

Pipe A has a large diameter with a maximum of 100 volts to flow through it.

Pipe B has a small diameter with a maximum of 15 volts to flow through it.

Source A has a pressure of 14 volts and is connected to pipe A.

Source B has a pressure of 14 volts and is connected to pipe B.

I have two meters.

I stick a voltmeter A in pipe A.... what would it measure ?

I stick a voltmeter B in pipe B... what would it measure ?

Both would probably measure 14 volts.

The difference would be the ampere.

The flow through pipe B would have to be faster, since it's smaller.

The flow through pipe A could be slower, since it's wider.

According to your explanation:

Sticking an ampere meter in pipe A should show a lower ampere.

Sticking an ampere meter in pipe B should show a higher ampere.

If this is how it works I think I understand it a little bit :)

However microelectronics are very very very small.

So for me it's hard to see the diameter and the resistance... (resistance is related to the material ;)) :)

Ok I think I am starting to get it.

Let's see even a more complex example:

Pipe A is split up into

Pipe A1 with a diameter of allowing 5 volts

Pipe A2 with a diameter of allowing 95 volts.

Now a good question is the following:

The voltage at pipe A1 would be 5 volts ? or would it blow up ?

It could be possible that the remaing 9 volts would simply go into pipe A2...

It probably depends on the strength of pipe A1...

At this point I really wouldn't know what the answer is ;)

Maybe it's related to the resistance or something... if it could resists 15 volts it might survive... But I don't think this is what resistance means ? or maybe it does ?

I thought resistance means how much voltage is lost....

Maybe this is the correct answer after all... if Pipe A1 has a resistance of

9 volts it could allow 5 volts to flow through it...

But what would happen to the other 9 volts ?

Would it go lost in Pipe A1 or would it flow through Pipe A2 without loss ?

I dont think the voltage would be simply halfed... since that's not how water behaves ;)

So the point is: The concepts pressure, flow, maybe even resistance are easy to understand... but how it behaves in reality especially in electronics is a little bit more difficult to understand ;)

Unless the answers are really simple... so I am curious what the answer(s) would be :) Especially the splitting up of the pipe question ;)

Bye, Skybuck.

Your amusement factor is declining fast.

I suggest ( if you're serious ) that you start reading a few decent books on electronic theory and practice. It'll come in handy !

Ohhh... hobby magazines such as Elektor ( if it still exists ) are a good source of info about practical circuits that can be easily built on a hobbyist basis. They are good foundations upon which to learn.

Graham

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bad

(voltageampere

electricity

for a

I am not trolling I am trying to understand it. But ok I can see how a dirty mind might think that's funny.

And in case you didn't understand that sentence here it is again:

So if the pressure of source of the voltage becomes to high the pipe blows ?

Without the smiley :D :P :D

Bye, Skybuck.

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water

dirty

?

Ok one more try:

So if the pressure of source of the voltage becomes to high the pipe blows up ? ;)

Bye, Skybuck.

If you aren't trolling, then might I suggest that the design of a completely new computer architecture is probably beyond someone who doesn't know about volts and amps. I'd guess about ten years of full time study might be enough to raise your general level of knowledge to a level at which the project wasn't a complete waste of everyone's time. In the meantime, please understand that even with the best will in the world (and whilst I may have been a little shirty yesterday, others have certainly indulged you) you simply aren't credible as an honest poster anymore.

Yes.

blows

Well that wasn't so hard ;)

Can you answer my other questions too, are did MIT dumb you down to much to answer it ? ;)

Bye, Skybuck.

I probably can, but you spelled "or" incorrectly and I've never been to MIT and, to paraphrase Arthur C. Clarke, "Any sufficiently rude Usenet poster is indistinguishable from a troll.".

Bye.

to

I had a feeling you weren't ever at MIT because you ain't dumbed down. It was just a joke ;)

Skybuck: "Having a conversation with a troll can be very usefull as well."

Thanks to a troll I found out my code is a universal code :D

How funny is that ? :):):):)

Bye, Skybuck ;)

I have updated this section to prevent any further confusion:

" Data bits: a,a,a,a,a,a,b,b,b,b,b,c,c,c,c (these bits can have value 0 or 1) "

(Since some people though these aaaa, bbb, ccc bits behaved like unary encoding (all ones or all zeros) This is not the case.

These bits can have any binary value, a zero or a one.

I have also included a new part for further clearity:

New part:

" The position of the bit in the information stream identifies if it is a marker bit or a data bit.

Positions:

0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2 0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9

Information stream: a,0,a,0,a,0,a,0,a,0,a,1,b,0,b,0,b,0,b,0,b,1,c,0,c,0,c,0,c,1

The data bits are located on "even" positions. (0,2,4,6,8,10,12,14,16,18,20, etc ) The marker bits are located on "oneven" positions. (

1,3,5,7,9,11,13,15,17,19, etc )

By reading a data bit, marker bit, data bit, marker bit, etc they can be seperated from each other. "

Bye, Skybuck.

This is probably even a better description ;)

" Data bits: a,a,a,a,a,a,b,b,b,b,b,c,c,c,c (each data bit can be a zero or a one) "

Hi,

And finally what better way than to explain it with an example ;)

" An example:

Data bits for field A = 1,0,0,0,1,0 Data bits for field B = 1,1,1,0,1 Data bits for field C = 1,0,0,1

Market bits for field A = 0,0,0,0,0,1 Market bits for field B = 0,0,0,0,1 Market bits for field C = 0,0,0,1

Data bits and marker bits interleaved for field A: 1,0,0,0,0,0,0,0,1,0,0,1 Data bits and marker bits interleaved for field B: 1,0,1,0,1,0,0,0,1,1 Data bits and marker bits interleaved for field C: 1,0,0,0,0,0,1,1

Interleaved field A,B,C stuck together (final encoded bitstream):

1,0,0,0,0,0,0,0,1,0,0,1,1,0,1,0,1,0,0,0,1,1,1,0,0,0,0,0,1,1 " Bye, Skybuck

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